1. Field of the Invention
The present invention relates to photographic light-sensitive elements having a dyed hydrophilic colloid layer. Particularly, the present invention relates to silver halide photographic light-sensitive elements having a hydrophilic colloid layer containing a dye which is easily decolored and removed at photographic processings and a basic polymer.
2. Description of the Prior Art
In silver halide photographic light-sensitive elements, a photographic emulsion layer or another layer is often dyed for the purpose of absorbing light in a specific wavelength range.
When control of the spectral composition of light incident upon a photographic emulsion layer is required, a colored layer is provided in a position farther from the support than the photographic emulsion layers in the photographic light-sensitive element. Such a colored layer is called a filter layer. Where a plurality of photographic emulsion layers is present, such as in a multilayer color photosensitive material, the filter layer sometimes as positioned between the photographic emulsion layers.
For the purpose of preventing the images from becoming indistinct, namely, halation caused by scattering of light rays passing through the photographic emulsion layers or after passage through and upon reflection at the interface between the emulsion layer and the support or the opposite surface of the photosensitive material and reentry into the photographic emulsion layers, a colored layer is positioned between the photographic emulsion layer and the support or on the opposite side of the support. Such a layer is called an antihalation layer. Where a plurality of photographic emulsion layers is present such as in a multilayer color photosensitive material, such a layer sometimes is positioned between the photographic emulsion layers.
For the purpose of preventing a reduction in image sharpness caused by scattering of light in the photographic emulsion layers (this phenomenon is called, in general, irradiation), the photographic emulsion layers are sometimes colored.
These layers which are colored often comprise hydrophilic colloids. Therefore, water soluble dyes are usually incorporated in the layers for coloration. Dyes used for such a purpose should have, of course, appropriate spectral absorption characteristics depending on the purpose of use and should satisfy the following requirements.
1. The dyes should be photochemically inert. Namely, the dyes should not have an adverse chemical influence upon the properties of the silver halide photographic emulsion layers, such as reduce the sensitivity, decay the latent images or generate fog. PA1 2. The dyes should be decolored or removed by dissolution during the photographic processings or not leave an undesired coloration on the photographic sensitive material after processing.
Many attempts have been made to discover dyes which satisfy these requirements. For example, oxonol dyes having a pyrazolone nucleus described in British Pat. No. 506,385, Japanese patent publications Nos. 22069/1964 and 13168/1968 and Japanese patent application (OPI) No. A 85130/1973, oxonol dyes having a barbituric acid nucleus described in U.S. Pat. Nos. 3,247,127 and 3,653,905, oxonol dyes described in French Pat. No. 1,401,588, benzylidene (or cinnamylidene) pyrazolone dyes described in British Pat. No. 584,609, U.S. Pat. Nos. 3,540,887, 3,615,546 and 3,687,670 and French Pat. Nos. 1,350,311 and 1,421,679, styryl dyes described in U.S. Pat. Nos. 2,298,733, 2,622,082, 3,384,487 and 3,652,283, British Pat. Nos. 1,075, 653 and Belgian Pat. No. 733,124, merocyanine dyes described in British Pat. No. 1,075,653 (those having formula IV), British Pat. Nos. 1,153,341 and 1,284,730 and French Pat. No. 1,401,588 (those having formula II) and cyanine dyes described in U.S. Pat. Nos. 2,843,486 and 3,294,539 and British Pat. No. 1,075,653 (with the exception of those having formulae I and II).
Many dyes which are decolored in photographic processing are decolored by sulfites (or bisulfites) present in the development processing solution or by sulfites and alkaline conditions (for example, as described in British Pat. No. 506,385).
In prior photographic processings, both dyes which are decolored by development processing as described above and dyes which are easily removed by dissolution from the photosensitive material without decoloring or with imperfect decoloring have been used as dyes for coloring the hydrophilic collid layer of photosensitive materials. The latter dyes not only color the photographic processing solutions or the water used for washing to cause environmental pollution, but also are not suitable for rapid photographic processing in which the processing time is shortened to be efficient, which has been employed recently. The dyes used for the photosensitive materials for such use should be not only decolor completely and rapidly during photographic processing such as development, but also they must have properties whereby the decolored dyes are easily removed from the photosensitive material during the subsequent processings and mainly during a washing step by water and do not form a color again in the photosensitive element or in the processing solutions or water for washing during the processing. Most hitherto known dyes are unsatisfactory for rapid photographic processing from the standpoints of decoloring rate at development, dissolution rate of the decolored or non-decolored dyes and irreversibility of the decoloring.
On the other hand, where the colored layer is a filter layer or is an antihalation layer positioned on the same side of the support as the photographic emulsion layer, commonly the selective coloration of such a layer without the other layers being substantially colored is required. This is because the dye causes not only a deterioration of the effect of the filter layer or of the anitihalation layer but also the dye adversely spectrally influences the other layers.
There are several processes for selectively coloring a specific hydrophilic colloid layer. However, the process which comprises incorporating a hydrophilic polymer containing a portion having a charge opposite to that of the dye ions together with a mordanting agent in the hydrophilic colloid layer, by which thedye is only present in the specific layer due to an interaction of the polymer and the dye molecule (it is believed that not only a charge attraction exists but also that a hydrophobic bond contributes to the attraction involved), is most widely used. Polymers derived from ethylenically unsaturated compounds having a dialkylaminoalkyl ester residue described in British Pat. No. 685,475, reaction products prepared by reacting polyvinyl alkylketones with aminoguanidine described in British Pat. No. 850,281 and polymers derived from 2-methyl-1-vinylimidazole described in U.S. Pat. No. 3,445,231 are used as mordanting agents. In using a mordanting process with such polymers, a portion of the dye in the dye containing layer often diffuses into other hydrophilic colloid layers when the dye containing layer contacts the hydrophilic colloid layers in a wet condition. The diffusion of the dye also depends, of course, upon the chemical structure of the mordanting agent and the chemical structure of the dye used.
Further, in using the above described high molecular weight mordanting agents, residual color is easily formed on the photosensitive material after photographic processing and particularly after a rapid processing in which the processing time is shortened. This is believed to be because although the bonding strength of the mordanting agent to the dye becomes fairly low in an alkaline solution such as a developer, some degree of bonding strength remains and the dye or reversibly decolored products remain in the mordanting agent containing layer. Although such a difficulty depends upon the chemical structure of the mordanting agent, it greatly depends upon the chemical structure of the dye.
On the other hand, a residual color is easily formed in the photosensitive elements after processing where an emulsified dispersion of a hydrophobic organic solvent, such as an aliphatic acid ester, an aromatic carvoxylic acid ester, a phosphoric acid aryl ester or an aromatic ether, etc., is included in any of hydrophilic colloid layers of the photosensitive element for the purpose of incorporating couplers or color stain preventing agents, etc. This is believed to be due to the fact that when the dye is included in a layer containing such an emulsified dispersion, or the dye diffuses from other layers into this layer, a portion of the dye incorporates into the interior of or at the surface of the emulsified dispersion particles, and the dye remains without being removed in a washing step with water.
Of the various water soluble dyes used for dyeing the hydrophilic colloid layers of photographic light-sensitive elements, oxonol dyes having a pyrazolone nucleus represented by the dyes described in British Pat. No. 506,385 are useful dyes, because these dyes are irreversibly decolored in developers containing sulfite and do not adversely influence the photographic properties of the photographic emulsions. However, these oxonol dyes are not sufficiently mordanted by the above described basic polymers and diffuse from the basic polymer containing layer to other layers.
On the other hand, where the colored layer is the filter layer, an absorption density above about 0.8 is necessary and often such a density must be obtained with a layer having a thickness of about 2 .mu.m or less. For example, a typical case is a yellow filter layer which is positioned below (closer to the support) a colored photosensitive layer of a multilayer color photosensitive element. In such a case, the dye must not only dissolve in the hydrophilic colloid in a high concentration but also should be mordanted surficiently by the basic polymers.